基质金属蛋白酶-9在大鼠弥漫性脑损伤中表达及与脑水肿相关性研究

Study of correlation between expression of matrix matalloproteinase-9 and cerebral edema after diffuse brain injury in rats

目的观察大鼠弥漫性脑损伤中基质金属蛋白酶(matrix metalloproteinase,MMP)- 9 mRNA表达和脑水肿的变化,探讨二者之间的关系。方法建立Marmarou大鼠弥漫性脑损伤模型,实时荧光定量逆转录-聚合酶链反应测定伤后不同时间MMP-9 mRNA的表达,干湿重法测定脑含水量并观察脑组织中炎症反应和毛细血管超微结构变化。结果外伤后1 h大鼠脑组织中MMP-9 mRNA开始增加,伤后12 h达到高峰并持续7 d(P＜0．01),14 d下降至对照组水平(P＞0．05)。脑组织含水量比假手术组明显增加,炎性反应和毛细血管的超微结构破坏更重。结论大鼠外伤后诱导MMP-9 mRNA表达增加,可能参与了弥漫性脑损伤后血管源性脑水肿的形成,从而加重了继发性脑损伤。

Objective To observe the expressions of matrix metalloprotcinase-9 mRNA and the change of cerebral edema after diffuse brain injury in rats and discuss their correlation. Methods Marmarou＇ s diffuse brain injury model of rat was made. Real-time quantitative RT-PCR, dry-wet method, histological techniques and electron microscope were used to determine the expressions of MMP-9 containing water in brain tissue and inflammatory reaction and ultrastructural changes of blood capillary at different time phases after truama. Results The expressions of MMP-9 mRNA started to increase at 1 hour, peaked at 12 hours （P 〈0. O1 ） and the increased MMP-9 mRNA level continued for one week in the traumatic group compared to the sham-operated group. At day 14, the MMP-9 mRNA levels declined to the level of the sham-operated group. The water content of brain tissues after diffuse brain injury was apparently higher in the traumatic group than in the sham-operated group, and inflammatory reaction was severe and the ultrastructures of blood capillary were disorganized in the traumatic group. Conclusion The expressions of MMP-9 mRNA are induced to increase after diffuse brain injury in rats. These finding suggests strongly that MMP-9 is involved in the cerebral edema of vascular origin, leading to aggravation of brain injury.